Improving Patient Selection for ¹⁸F-FDG PET Scanning in the Staging of Gastric Cancer

UNLABELLED: Standard pretreatment staging for gastric cancer includes CT of the chest, abdomen, and pelvis; gastroscopy; and laparoscopy. Although (18)F-PET combined with CT has proven to be a useful staging tool in many cancers, some gastric cancers are not (18)F-FDG-avid and its clinical value is still debatable. METHODS: Gastric cancer patients who underwent staging (18)F-FDG PET scans from 2002 to 2013 at the Peter MacCallum Cancer Center were retrospectively analyzed, and a systematic review was also conducted using PubMed between 2000 to March 2014 to investigate clinicopathologic parameters associated with (18)F-FDG avidity. A pretreatment PET scoring system was developed from predictors of (18)F-FDG avidity. RESULTS: Both the retrospective analysis of the patients and the systematic literature review showed similar significant predictors of (18)F-FDG avidity, including large tumor size, non-signet ring cell carcinoma type, and glucose transporter 1-positive expression on immunohistochemistry. A PET scoring system was developed from these clinicopathologic parameters that allowed (18)F-FDG-avid tumors to be detected with a sensitivity of 85% and a specificity of 71%. CONCLUSION: A pretreatment PET scoring system can assist in the selection of patients with gastric adenocarcinoma when staging (18)F-FDG PET is being considered.